The invention relates to a compact micromotion translator utilizing piezoelectric (PZTs) transducers that are operated to produce precision, tilt-free, linear translation of a translation plate relative to a fixed member.
Various micromotion translators are used in optical measurement instruments to translate an optical test surface or reference surface for the purpose of making highly accurate measurements of optical phase. To accomplish this result, it is necessary to translate an optical reference surface without tilting through a small extremely precise distance relative to a test surface. A typical translation distance may be approximately one micron. Various PZT actuated micromotion translators, such as the one shown in U.S. Pat. No. 4,577,131 (Soobitsky), issued Mar. 18, 1986, are known. The relatively large sizes and the configurations of most known micromotion translators causes them to be susceptible to tilt and mechanical vibrations. In optical interferometers, tilt during translation and mechanical vibration make it difficult or impossible to achieve the accuracy needed for very precise measurement of optical path differences between a reference surface and a test surface. Prior micromotion translators do not achieve translation that is as linear and tilt-free as is desirable for many optical measurement.
There is a presently unmet need for a compact, vibration-resistant, piezoelectric micromotion translator capable of very precise, linear, tilt-free translation of a member through short distances, for example, in the range of a few microns.